s2konroids

When foot is off accelerator and your coasting the injectors stop spraying.

lower

You'd have to know a bit more to be able to calculate that.

When coasting the engine is using enough fuel to keep it idling, but there is no engine braking so you will travel further.

When coasting in gear you use no fuel but the engine is slowing you down so you won't travel as far.

It would depend on how far you needed to coast.

Dracoro

How steep is the hill, how fast you are going, when do you need to stop, is there traffic behind you etc. All factors need to be taken in.

"sometimes" it *may* use less fuel to idle (as you can coast for longer) rather than cost in gear but I would say these situations are rare and you still have the issue of not being in gear if you wanted to suddenly accelerate.

phil121081

yeah thats what i was getting at really...I wonder how much fuel is used at idling (very little i suspect) and how far that fuel would get you to bridge the gap between the distances travelled whilst coasting and 'in-gear'....I wont lose too much sleep over this.

What I can say is that on the same journey I get an indicated 55mpg whereas my wife gets 48mpg in the Audi, so I am clearly the more 'economical' driver.

Although not braking for bends get's her a little on edge at times...haha.

Nickamsweet

that's the main point I think in this thread... we all know that idling uses fuel etc but if you are 'engine braking' then do you still need to inject fuel during decelleration or does it just fire the usual idle amount as the throttle body is in idle position??

Dracoro

No, it uses NO fuel.

Which makes sense, as why would it need it? The coasting in gear is turning the engine.

If you want an analogy, imaging a cycle, you're going down a hill, you take your feet off the pedals (i.e stop putting energy in) and the pedals can still turn even no there's no power going to them.

Chad!

When the time comes that I worry about how much fuel is or isn't used coasting down a hill, I'll sell up and get a very economical car. For how much coasting is done, you'd probably be doing very well to save a litre in a year. I'm sure you could cut back on something and save more than that in a week, maybe even per day. That would then save all those extra pennies for more

m1bjr

I tried a 'frugal day' in the little bimmer.

Reset the computer and slipstreamed a coach at 60-62mph up the M5/m6 for almost 120 miles.
Coasting and slipping and being very soft all the way.

80mpg indicated.

Did some town driving, filled up and it calculated accurately down to 71mpg on combined cycle.

So you can keep you crappy Jap Pious hybrid abortions, and little toytown mercs.



If you are even thinking about this in an S2000, time to sell it buddy...

richmc

Theres a route I take from time to time in the wifes Jizz, it has one of those mpg readouts. Normal driving gets me 45 or so mpg, keeping in 4th or 5th and coasting when I can I can get up to 54 mpg by the time I'm home, it's a bit of a chalenge for me.

Now I've no chance of improving the mpg performance of the S, I just have to VTEC!

Will probably be trading in the Jizz for a Jizz hybrid soon so I will have a new challenge, as the battery is charged up guess when? During braking and in gear coasting.

m1bjr

If you can show me a family sized hybrid for £26k that performs like the 318/118d and can do all this.

I'll get one next.

Hybrid cars=fail
Electric cars with batteries=big fail